There are various types of diode phase shifters using PIN-type diodes, e.g. interference phase shifters, having a high power response and a wide pass band, and line-section phase shifters such as the switching phase shifter which, compared with the above-mentioned type, has smaller overall dimensions and constant losses related to phase displacement. Interference and line-section phase shifters are suitable for planar structures and the choice of one or the other type is based on such criteria as the number of phase-displacement diodes, the standing-wave ratios, the insertion losses and the power response.
However, these prior-art phase shifters utilize transmission lines of specific lengths and consequently have phase displacement, loss and standing-wave-ratio characteristics which vary with frequency.